This invention relates to tool supports for machine tools for cutting grooves, and, more particularly, to tool supports for tools for cutting deep grooves in the face of a workpiece.
The art of cutting grooves in the face of a metal workpiece, particularly cutting relatively deep grooves, presents a unique problem because of the extreme pressures placed upon the cutting tool or insert (hereinafter "insert"), without the space available beneath the insert for its support where the insert must enter the groove as the insert advances into the workpiece. While tool supports or holders have been developed to support inserts, for example the holder shown in U.S. Pat. No. 3,611,525, and may be adequate where cuts or grooves are to made in the side of the workpiece, those holders do not provide sufficient support beneath the insert to permit the cutting of a deep groove in the face of the workpiece. As noted in aforementioned patent, the force on the insert is essentially downward, and if the insert overhangs the support by more than a minimal distance, a very large moment is generated which often causes the insert to break, particularly if the insert is formed of a relatively brittle metal or alloy such as a carbide alloy.
One proposal to counter the forces tending to cause the insert to break where it must overhang the support is to increase the height of the insert to provide added strength against breaking forces. However, as noted in U.S. Pat. 3,611,525, increasing the height of the insert decreases the ability to support the insert against moving sideways or tilting. A additional problem with an insert of increased height encountered where a deep groove is to be cut, is that the additional height will interfere with or bind the insert in the groove as the insert penetrates into the workpiece.
Another proposed improvement in tool supports, is shown in U.S. Pat. No. 3,894,322. However, in that patent inserts with only relatively short overhangs are apparently contemplated, and no additional provision is made to support inserts for deep grooving of the face of a workpiece. A frusto-conical surface is provided between a front side surface of the narrow wall of the holder which supports the insert and the shank portion of the holder presumably to strengthen the former.
None of the proposed tool support arrangements, for example, those noted above, satisfactorily solve the problem of providing support for inserts for cutting deep grooves in the face of a workpiece.